100 Gbps Over Copper Possible!

Penn State University engineers say that a transmission rate of 100 G bps is obtainable over in-expensive Category 7 copper cables, but only on a length of 100 meters or less.

This research has been done by a team including two graduate students in electrical engineering, Ali Enteshari and Jarir Fadlullah. The team was supervised by Mohsen Kavehrad, professor of electrical engineering. Working with NEXANS, the company that manufactures the cable, they have examined the possibility of sending digital data at a rate of 100 gigabits per second over 100 meters of Category-7 copper cable.

Using information on specifications and characteristics of the cables from NEXANS, the researchers modeled the cable with all its attributes including modeling crosstalk. They then designed a transmitter/receiver equipped with an interference canceller that could transfer up to 100 gigabits using error correcting and equalizing approaches.

Ethernet cable like the Category 7 is made up of four pairs of twisted wires shielded to reduce crosstalk. Category 7 is heavier weight wire with better shielding than Category 5 cable. Kavehrad’s group did similar analysis on the Category 5 cables in 2003.

“A rate of 100 gigabit over 70 meters is definitely possible, and we are working on extending that to 100 meters, or about 328 feet,” said Enteshari. “However, the design of a 100 gigabit modem might not be physically realizable at this time as it is technology limited. We are providing a roadmap to design a high speed modem for 100 gigabits.”

The researchers believe that two or three generations in the future, the technology of chip circuitry will allow these modem designs to be built. Currently, chip design is at about 65 nanometers, but they expect in the next two generations to get to what is required, said Kavehrad.

The amount of data encompassed by 100 gigabits is amazing. The entire Encyclopedia Britannica contains 1 gigabyte of information. A byte is equivalent to 8 bits, so 1 Gigabyte is equal to 8 gigabits. A rate of 100 gigabits per second over 100 meters is the transmission of 12.5 Encyclopedia Britannica sets per second.